J. Robert Oppenheimer’s grandson has pointed out a ‘serious’ historical error with the film

The grandson of J. Robert Oppenheimer has come out swinging over a small detail in Christopher Nolan's film.

Oppenheimer is a biopic about the theoretical physicist dubbed the 'father of the atomic bomb'.

However, the script was largely based on the 2005 biography American Prometheus by Kai Bird and Martin J. Sherwin.

It details the scientist's life, the Manhattan project, and, of course, the explosion that changed the course of history.

While it does an incredible job at revealing everything that led up to the first atomic blast, Charles Oppenheimer has called out one particularly debatable moment in the film.

Universal Pictures

He told TIME: "The part I like the least is this poison apple reference, which was a problem in American Prometheus. If you read American Prometheus carefully enough, the authors say, 'We don't really know if it happened'."

This part of the film happens right at the start.

It shows Oppenheimer (played by Cillian Murphy) studying at Cambridge and struggling with homesickness while under the tutorage of Patrick Blackett at the Cavendish Laboratory.

He finds Blackett so demanding that he decides to leave a poisoned apple and a visiting scientist nearly takes a bite out of it.

However, Charles Oppenheimer believes this is grossly inaccurate.

"There's no record of him trying to kill somebody," he told TIME.

"That's a really serious accusation and it's historical revision. There's not a single enemy or friend of Robert Oppenheimer who heard that during his life and considered it to be true."

Universal Pictures

He said the authors of American Prometheus 'got it from some references talking about a spring break trip', however it wasn't verifiable information.

Charles understands when facts might get dramatized for the big screen or stretched a little.

But he added: "It bothers me that it was in the biography with that emphasis, not a disclaimer of, this is an unsubstantiated rumor that we want to put in our book to make it interesting."

The grandson of J. Robert visited the set a few times during filming and had some good chats with director Christopher Nolan about how they were handling the story.

He was preparing to not like it when he saw it in the cinema, however was surprised at how much it stuck to the stories he had been told about his grandfather.

"I thought it told a compelling story and I could just take it as art that was really engaging," he told TIME.

"I was really happy to have that reaction. I didn't expect it."